Removable lock



2 Sheets-Sheet l INVENTOR.

ATTORNEY.

March 9, 1937. v P. w. OLSON REMOVABLE LOCK Filed June 10, 1955 (0'.Olson March 9, 1937. P. w. OLSON REMOVABLE LOCK Filed June 10, 1935 2Sheets-Sheet 2 1 N VENTOR. Pfizigia (fl. Oboil %44MW ATTORNEY.

Patented Mar. 9, 1937 UNITED STATES PATENT OFFICE REMOVABLE LOCKApplication June 10,1935, Serial No. 25,709

8 Claims.

This invention relates to improvements in locks, and more particularlyto the provision of releasable means for retaining the tumbler plug inthe lock casing barrel.

It is often desirable to change looks so that the old keys can no longerbe used, and in some instances it has been necessary to change all ofthe locks in large buildings owing to a general change in tenants. Suchinstances involve the removal and replacement of several thousand lockplugs, and consequently a large expense accumulates. Accordingly oneobject of this invention is to provide a lock having a readily removableplug, but which to prevent illicit removal requires the use of aspecially formed removal key, and also the operation of otherinstrumentalities, as well as a knowledge of the particular manner ofremoving.

Further objects of the invention are to provide a plug retainingconstruction in which the plug is not apt to become released in thenormal service operation of the lock; to provide such means which can beoperated entirely from the face of the look so that it is not necessaryto open the door to obtain access to screws or pins in the edge or innerside of the door; and to provide means for releasably retaining the plugwhich is entirely under the protection of the lock itself, whether thedoor is open or closed.

' Other objects and advantages will become apparent in the followingdescription, taken with reference to the accompanying drawings, in whichan illustrative embodiment of the invention is shown.

Fig. 1 is a longitudinal cross section of the key operated locking unitwhich, as in well known practice, is inserted in the door or thefastening mechanism of other forms of closures; Fig. 2 is a transversecross section, looking from the rear, taken on the line 2-2 of Fig, 1;

Fig. 3 is a transverse section on the line 3-3 of Fig. 1;

Fig. 4 is a front elevation of the unit; Fig. 5 is a longitudinalsection of the barrel or housing member;

Fig. 6 is a section taken on the line 66 of Fig. 1 with the plugsectioned on the two different planes of the tumblers;

Fig. 7 is a. diagrammatic view showing the master key operation; and

Fig. 8 is a similar diagrammatic view showing the operation of thetumblers by the insertion of the replacement key.

A cylindrical barrel housing or casing 9 is provided, which has astepped concentric counterbore NJ in the rear end thereof; an eccentricplug receiving bore II; and a smaller bore [2, below the bore I I, bothof which extend through the barrel.

Seated in the bottom of the counter-bore l0 is a stationary plate l3,secured in position by means of screws l4; and an end cover plate [5 issecured in the end of the barrel by peening over the metal at the edges.

In the installation, the barrel is fixedly mount- 10 ed in position,which may be accomplished in any well known manner.

In the outer face of the barrel is a stepped counter bore l6, concentricwith the bore H, for receiving a keyhole plate I! which is mount- 15 edon the outer end of a cylindrical tumbler plug I8; and in the walls ofthe bore H is provided a plurality of annular grooves l9 and a pair ofoffset, oppositely disposed longitudinal grooves 20. bottom of thecounter bore l0 into the counter bore I6 and intersect each of theridges 2| between the annular grooves 19. A small pocket 22 is alsoprovided in the rear portion of the bore I! and intersecting the bore l2to provide 5 space for a plug retainer cam 23.

' Thus the plug I8 is inserted in a bore having annular circumferentialgrooves intersected by longitudinal grooves forming notches 24, whichprovide locking surfaces for preventing the rotation of the plug. Theplug is provided with a set of latch key tumblers 25, which normallyregister with the ridges 2| and engage in the notches 24 to lock theplug against rotation.

Latch tumblers 25 are arranged in a row along 35 one side of a keyway26, which extends longitudinally through the plug l8 and the plate l1;and at the opposite side of the keyway is provided a set of master keytumblers 21, which normally register in the grooves l9 and abut 40against the sides thereof, and prevent endwise movement of the plug.

The tumblers are all similar in construction, except for variations incertain dimensions to provide the different series of combinations. 45Each tumbler has a lug 28, which projects into the keyway 26; and thetumblers are individually pressed outwardly to project from the surfaceof the plug in one direction or the other by means of small springs,which are inserted in notches 50 280,, provided in the outer edges ofthe tumblers, and seat against pins 29 inserted through the 1 walls ofthe plug.

Thus in service operation the set of tumblers 25 may be withdrawn intothe plug by the inser- 55 Said grooves 20 extend from the tion of alatch key, not shown, which is provided with grooves having suitabledeviations for so operating the tumblers. The plug may then be rotatedto operate the look by means of the cam 39, which is provided at therear end of the barrel.

The cam 38 is fixedly mounted on the shaft 34 of a gear 35, which isconfined between the plates I3 and i5 and meshes with a gear 35, whichis provided with a hub 31, which extends through the plate I3. The hub31 is provided with a tongue 38 which enters the keyway at the rear endof the plug.

In this manner the axis of the cam may be located in the lower portionof the barrel, while the plug is mounted in the upper portion. The plugis urged forwardly by means of a bifurcated spring plate 353, which isriveted to the inner side of the plate l3 and straddles the reducedinner end portion 49 of the plug and bears against a shoulder 44 formedon the plug.

The shoulders of the tongue portion 38 of the gear hub 37 are locatedfar enough back, and the depths of the counterbore I6 is such that theplug may be pushed into the barrel against spring 39 when the master keytumblers 27 are drawn inwardly. This moves the tumblers 25 into theannular grooves l9 so that the plug is then free for rotation, in themaster key operation of the look.

For preventing endwise withdrawal of the plug when a master key 42 isinserted, a retainer tumbler 43 is provided which engages behind a ring44, which is fixedly mounted in the inner portion of the bore l I andsurrounds the plug, as clearly shown in Fig. l and Fig. 3. Accordinglythe plug cannot be withdrawn until a replacement key45, which has agroove 45a for withdrawing the master key tumblers, which groove isextended to also withdraw the retainer tumbler 43; but toremove it, theplug must be rotated into lockin normal position so that the latch keytumblers 25 will pass out through the longitudinal grooves 29.

As will be understood, the master key 42 is shouldered so that it cannotbe inserted to a sufficient depth to operate the tumbler 43, or the endportion of the groove 42a in the master key may be formed so that itdoes not fully withdraw the tumbler 43.

In addition to the above described releasable plug retaining means, Iprovide the cam 23 which is keyed on the inner end of a rod or shaft 55,which is inserted in the bore l2.

On the inner portion of the plug i8 is provided a circumferential groove46 for the engagement of the cam 23, and the bottom of the groove isflattened at one side of the plug to provide a depression 41 (Fig. 3)for permitting the rotation of the cam when the plug is rotated to bringthe depression 4? opposite and into registration with the end 48 of thecam which is made concave to closely cooperate with the circular bottomportion of the groove. The cam is urged to rotate into engagement in thegroove by a coil spring 49, and

is provided with a stop projection 59, which strikes against the wall ofthe pocket 22, as clearly shown in Fig. 3, and governs the position ofthe cam so that the end portion thereof does not bear against the bottomof the groove 45 and interfere with the turning of the plug in ordinaryservice operation.

The front end of the shaft 55 has a transverse slot 49 for receiving abladed tool for turning the shaft to disengage the cam 23. In order toprevent the use of any kind of an implement, such as a screw driver, aslotted plate 59 may be secured in the opening of the bore I2.

Thus to remove the tumbler plug, the replacement key 45 which fits thelock must be inserted in the keyway to withdraw the master key tumblers21 and the retainer plunger 43. Then the plug is pushed rearwardlyagainst the action of the spring 39 to move the latch key tumblers 25out of the notches in the ridges 2| and into the circumferential groovesl9. This frees the cylinder plug l8 for rotation, and the key is turnedto bring the depression 41 opposite the cam so that the cam may berotated.

While the key is being held in this position with one hand, a bladedtool is inserted through the orifice plate 5|] and engaged in the slot49 to rotate the cam 23 clockwise, looking from the front against theaction of the spring 49.

Accordingly the cam must be held out of engagement until the tumblerplug is turned back to normal position so that the row of latch keytumbler wells pass out through the longitudinal slots 29.

With the proper tools, it is manifest that the locks can be changedeasily and quickly, while at the same time unauthorized removal of theplug is very difficult to accomplish.

Having thus described my invention, I claim:

1. In a lock having a barrel and a key operated tumbler cylinder mountedin the barrel for rotation, the cylinder having a peripheral groovehaving a depression in its bottom surface and a cam rotatably mounted inthe barrel adjacent the cylinder, the cam being rotatable into or out ofengagement in said groove when the cylinder is rotated to bring saiddepression opposite the cam, and the cam having a concave end surfacecooperating with the bottom of the groove to prevent its rotation whenthe said bottom depression is not in registration therewith.

2. In a lock having a barrel and a key operated tumbler cylinder mountedin the barrel for rotation, the cylinder having a peripheral groovehaving a depression in its bottom surface, a cam rotatably mountedadjacent the cylinder for engaging in said groove to prevent withdrawalof the cylinder, the cam having a concave end surface for cooperatingwith the bottom of the groove for locking the cam in engagement, aspring for rotating the cam into the groove, and a stop governing thelocking position of the cam so that said end surface is held out offriction producing contact with the bottom of the groove.

3. A look comprising a barrel having annular and longitudinalintersecting grooves in the walls thereof, a key operated plug insertedin the bore, a spring pressing the plug forwardly, the plug having a setof latch key tumblers normally registering with the ridges between theannular grooves and engageable in the notches formed by the longitudinalgrooves in said ridges, and the plug having a set of master key tumblersnor mally registering in the grooves to prevent longitudinal movement ofthe plug, a ring fixedly mounted in the rear portion of the bore, and aplug retaining tumbler contained in the plug for engagement behind thering so that the plug can only be removed by withdrawing the master keyand. the plug retaining tumblers and placing the plug in lockingposition so that the latch key tumblers will pass out through thelongitudinal grooves.

4. The combination of claim 3 further including other retaining meansnormally engaged with the plug and releasable therefrom only when theplug is rotated away from locking position.

5. A look comprising a barrel having annular and longitudinalintersecting grooves in the walls thereof, a key operated plug insertedin the barrel, a set of latch key tumblers in the plug normallyregistering with the ridges between the annular grooves and engageablein the notches formed by the longitudinal grooves in the ridges, a setof master key tumblers normally registering in the grooves to preventlongitudinal movement of the plug, the plug also having an annulargroove at its innermost end, a cam mounted in the barrel and having ashaft upon which it is rotatable extending to the front of the barrelfor operating the cam from the face of the barrel to release the plugfor removal from the barrel when the master key tumblers are withdrawn.

6. A look comprising a barrel having annular and longitudinalintersecting grooves in the walls thereof, a key operated plug insertedin the barrel, a spring pressing the plug forwardly, the plug having aset of latch key tumblers normally registering with the ridgesbetweenthe annular grooves and engageable in the notches formed by thelongitudinal grooves in said ridges, a separate set of master keytumblers normally registering in the grooves to prevent longitudinalmovement of the plug, the plug having an annular groove at its inner endand means including a cam mounted in the barrel at the side of the plugand rotatable from the front of the barrel for normally engaging inthegroove of the plug, the groove being of suflicient width to maintainengagement with the cam when the plug is pressed longitudinally againstthe spring a distance equal to the Width of the ridges within thebarrel.

7. A structure in accordance with claim 6 in which the plug has a keywayextending through it, and a plug operated member is mounted at the rearof the barrel and includes a hub having a tongue which enters the keywayat the rear of the plug for operative movement therewith.

8. In a lock having a barrel and a key operated tumbler cylinderrotatably mounted in the barrel, the cylinder having a peripheral grooveat the inner end thereof, a cam rotatably mounted adjacent the cylinderfor engaging in said groove to prevent withdrawal of the cylinder, andmeans extending within the barrel from the cam toward the front of thebarrel with a transverse slot in the end thereof which lies at adistance within the barrel for receiving a bladed tool inserted from thefront of the barrel for operating the cam.

PHILLIP W. OLSON.

